Vehicle control systems and methods

ABSTRACT

Systems and methods for controlling the speed and direction of vehicles such as tractors.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. patent applicationSer. No. 13/051,711, filed Mar. 18, 2011, now U.S. Pat. No. 8,474,841,which is a divisional of U.S. patent application Ser. No. 11/874,130,filed Oct. 17, 2007, now U.S. Pat. No. 7,914,022, which claims priorityto U.S. Provisional Patent Application Ser. No. 60/829,875, filed Oct.17, 2006. The entire text of each of the above-referenced disclosures isspecifically incorporated by reference without disclaimer.

BACKGROUND

The present invention relates in general to systems and methods forcontrolling the movement of vehicles, and more particularly to systemsand methods of coordinating the steering and speed inputs from anoperator to control the speed and direction of a vehicle.

SUMMARY

Certain embodiments of the present disclosure comprise a vehicle controlsystem comprising: a first plate that has two cams and that rotates in afirst plane; and a pair of drive cam plates coupled to the first plate,both drive cam plates being rotatable at the same time in response to aspeed input. In specific embodiments, the first plate has a center ofrotation, the two cams are slots in the first plate, and the slots aresymmetrical about an axis passing through the center of rotation. Incertain embodiments, the first plate may be gearless.

Other embodiments of the present disclosure comprise: a steering pinion;a sector gear that engages the pinion; a plate that is coupled to thesector gear, the plate having a pair of cams; two followers, one ofwhich engages one of the cams and the other follower engages the othercam; and a linkage system coupled to the followers, the linkage systembeing coupled a transmission system. In certain embodiments, the linkagesystem includes two linkages, the transmission system includes twotransmissions, and one linkage is coupled to and delivers a drive inputto one of the transmissions and the other linkage is coupled to anddelivers a drive input to the other transmission. In specific exemplaryembodiments, each drive input is based on (i) a speed input or (ii) aspeed input and a steering input. In certain embodiments, the plate hasa center of rotation, the cams are slots in the plate, and the slots aresymmetrical about an axis passing through the center of rotation.Certain embodiments may comprise a housing in which at least thesteering pinion, the sector gear, the plate, and the followers aresubstantially sealed.

Certain embodiments of the present disclosure comprise a steeringpinion; a rack that engages the pinion, each end of the rack beingcoupled to a steerable structure; a sector gear that engages the pinion;and a linkage system coupled to the sector gear such that rotating thesteering pinion manipulates the linkage system, the linkage system beingconfigured to provide at least one drive input to a transmission system.In specific exemplary embodiments, the linkage system includes twolinkages, the transmission system includes two transmissions, and onelinkage is coupled to and delivers a drive input to one of thetransmissions and the other linkage is coupled to and delivers a driveinput to the other transmission.

Certain exemplary embodiments of the present disclosure comprise asteering pinion; a sector gear that engages the pinion; an assemblycoupling the sector gear to a pair of beveled gears; and a linkagesystem coupled to the beveled gears such that rotating the steeringpinion manipulates the linkage system, the linkage system beingconfigured to provide at least one input to a transmission system.

Additional exemplary embodiments of the present disclosure comprise asteering pinion; a sector gear that engages the pinion; a first platecoupled to the sector gear, the first plate rotating in a first plane inresponse to rotation of the steering pinion; and a pair of drive camplates coupled to the first plate. In certain embodiments, the firstplate has two slots, and the system also includes two followers whereone follower rides in one of the slots and the other follower rides inthe other slot. In specific embodiments, each drive cam plate mayinclude a slot.

Additional embodiments of the present disclosure comprise a steeringpinion; a rack that engages the pinion, each end of the rack beingcoupled to an Ackermann steering assembly; a sector gear that engagesthe pinion; a plate coupled to the sector gear, the plate having a pairof cams; two followers, one of which engages one of the cams and theother follower engages the other cam; two translating gears, one ofwhich is coupled to one of the followers and the other translating gearis coupled to the other translating gear; two rotating gears, one ofwhich engages one of the translating gears and the other engages theother translating gear; two steering arms, one of which is coupled toone of the rotating gears and the other steering arm is coupled to theother rotating gear, the two steering arms being able to rotateindependently of each other; two drive cam plates, one of which iscoupled to one of the steering arms and the other drive cam plate iscoupled to the other steering arm; a shaft coupled to both drive camplates; and a linkage system that couples the drive cam plates to atransmission system.

In specific embodiments, the linkage system includes two linkages, thetransmission system includes two transmissions, and one linkage iscoupled to and delivers a drive input to one of the transmissions andthe other linkage is coupled to and delivers a drive input to the othertransmission, where each drive input is based on either a speed input oron a speed input and a steering input. In certain embodiments, eachdrive cam plate includes a slot in which a drive cam plate followerrides, the position of each of the drive cam plate follower beingcontrolled by one of the steering arms.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 illustrates a top view of one exemplary embodiment of a vehiclecontrol system.

FIG. 2-4 illustrate perspective views of the embodiment of FIG. 1.

FIG. 5 illustrates a side view of the embodiment of FIG. 1.

FIG. 6 illustrates a perspective view of the embodiment of FIG. 1 inaddition to other components.

FIG. 7 illustrates a top view of a component of FIG. 1.

FIG. 8 illustrates a side view of a component of FIG. 1.

FIGS. 8A and 8B illustrate top and side views of an alternate embodimentof a vehicle control system component.

FIGS. 9A-9D illustrate detailed views of a component of FIG. 1.

FIGS. 10A-10D illustrate detailed views of a component of FIG. 1.

FIGS. 11A-11B illustrate detailed views of a component of FIG. 1.

FIGS. 12A-12B illustrate detailed views of a component of FIG. 1.

FIGS. 13A-13B illustrate detailed views of a component of FIG. 1.

FIGS. 14A-14B illustrate detailed views of a component of FIG. 1.

FIGS. 15-18 illustrate detailed views of a component of FIG. 1.

FIG. 19 illustrates data relating to the geometric and physicalrelationship of various components in a vehicle control system.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

The terms “comprise” (and any form of comprise, such as “comprises” and“comprising”), “have” (and any form of have, such as “has” and“having”), “contain” (and any form of contain, such as “contains” and“containing”), and “include” (and any form of include, such as“includes” and “including”) are open-ended linking verbs. As a result, asystem or method that “comprises,” “has,” “contains,” or “includes” oneor more elements possesses those one or more elements, but is notlimited to possessing only those one or more elements or steps.Likewise, an element of a system or method that “comprises,” “has,”“contains,” or “includes” one or more features possesses those one ormore features, but is not limited to possessing only those one or morefeatures. Furthermore, a structure that is configured in a certain waymust be configured in at least that way, but also may be configured in away or ways that are not specified.

The terms “a” and “an” are defined as one or more than one unless thisdisclosure explicitly requires otherwise. The terms “substantially” and“about” are defined as at least close to (and includes) a given value orstate (preferably within 10% of, more preferably within 1% of, and mostpreferably within 0.1% of). Metric units may be derived from the Englishunits provided by applying a conversion and rounding to the nearestmillimeter.

Unless otherwise noted, the figures and drawings included in thisdisclosure are to scale (in terms of proportions).

FIGS. 1-5 shows aspects of one embodiment of the present systems. FIG. 6shows some additional aspects of another embodiment of the presentsystems. FIGS. 7- 14B illustrate detailed views of individual componentsof the present systems. Referring initially to these figures, vehiclecontrol system 100 comprises housing 112, steering shaft input pinion110 (or, more broadly, steering pinion 110), sector gear 120, cam plate130 (or, more broadly, plate 130) having a first cam slot 132 and asecond cam slot 134, first follower 142, and second follower 144. Firstcam slot 132 may be characterized more generally as a first cam, andsecond cam slot 134 may be characterized more generally as a second cam.Vehicle control system 100 further comprises first bevel gear set 152(which includes horizontal bevel gear 155 and vertical bevel gear 157)as well as second bevel gear set 164 (which includes horizontal bevelgear 165 and vertical bevel gear 167). In some embodiments, thehorizontal bevel gears may be characterized as translating gears, andthe vertical bevel gears characterized as rotating gears. System 100also comprises first shaft 176 coupled to first steering arm 172, firstspeed cam or drive cam 192 (which may be coupled to first steering arm172 through a linkage that includes one or more slots and pins), andsecond shaft 178 coupled to second steering arm 174, and second speedcam or drive cam 194 (which may be coupled to second steering arm 174through a linkage that includes one or more slots and pins). In FIG. 1,the top portion of housing 112 has been removed to reveal the componentsinside.

During operation, steering pinion 110 meshes with sector gear 120,causing sector gear 120 to turn when steering wheel 101 is turned.Sector gear 120 (one embodiment of which is also shown in FIGS. 15-18)is coupled to plate 130 in such a manner that plate 130 turns whensector gear 120 is turned. Plate 130 rotates in a plane. For ease ofillustration, this plane will be referred to as the “horizontal” planeand a plane perpendicular to this plane will be referred to as the“vertical” plane. In certain embodiments, input pinion 110 is orientedat a 26 degree angle to the plane in which plate 130 rotates. Thisnomenclature does not limit the orientation of vehicle control system100 or its components, and other embodiments may include orientationsother than those shown in FIG. 1. Slots 132 and 134 in plate 130 engagefirst follower 142 and second follower 144, respectively, causing themto move as plate 130 moves.

First follower 142 is coupled to first horizontal bevel gear 155, whilesecond follower 144 is coupled to second horizontal bevel gear 165 (alsoshown in FIG. 6). Therefore, the movement of followers 142 and 144causes the movement of horizontal bevel gears 155 and 165, respectively.Horizontal bevel gears 155 and 165 engage vertical bevel gears 157 and167, respectively, and cause them to move when the horizontal bevelgears move. Vertical bevel gears 157 and 167 rotate in the verticalplane. Vertical bevel gears 157 and 167 are coupled to shafts 176 and178, respectively, such that rotation of vertical bevel gears 157 and167 causes shafts 176 and 178 to also rotate. First steering arm 172 andsecond steering arm 174 are coupled to shafts 176 and 178, respectively,and therefore rotate or pivot with shafts 176 and 178. Shafts 176 and178 are capable of rotating independently of each other and each havetheir proximal ends supported by bearing 179. Bearing 179 may includeflange bearings, sleeve bearings, ball bearings, or any other suitablebearing system that allows shafts 176 and 178 to rotate independently ofeach other.

As steering arms 172 and 174 move, a first link and a second link (whichare coupled to steering arm 172 and 174, respectively) also move. Theselinks are not shown in FIG. 1-5 but are shown as links 182 and 184 inFIG. 6. One end of link 182 is coupled to slot 206 of first drive cam192 and one end of link 184 is coupled to slot 208 of second drive cam194. Drive cams 192 and 194 also may be referred to as drive cam plates.As steering arms 172 and 174 pivot, links 182 and 184 change positionwithin slots 206 and 208.

Each link 182, 184 is coupled to a drive rod 183, 185 (shown in FIG. 6).Each drive rod 183, 185 is coupled to a pintle shaft that delivers adrive input to a transmission (e.g., a hydrostatic transmission or acontinuously-variable transmission (also referred to as an infinitelyvariable transmission)) that controls the direction and speed ofrotation of a drive wheel of the vehicle. The drive input can be basedon a speed input from an operator (e.g., such as a speed input deliveredthrough movement of foot pedal 105, as discussed in more detail below),such as when the operator wishes to travel in a straight direction, oron both a speed input and a steering input, such as when the operatorwishes to turn. The two transmissions in this example can be consideredas components of a transmission system, and the drive rods and pintleshafts can be considered as components of a linkage system that deliversat least one drive input to the transmission system. The articulation ofthe steering input device (e.g., steering wheel 101) affects theposition within cam slots 206 and 208 of a pair of links 182 and 184,which affect the drive input that will be transmitted to thetransmission system through the drive rods and pintle shafts when theoperator actuates the speed input (e.g., when he or she presses down onthe gas pedal).

Various positions of the pin of one of these links in slot 206 of cam192 are shown in FIG. 5, and this figure shows one manner in which cam192 (and, as a corollary, cam 194) can rotate when an operator actuatesthe speed input. Cams 192 and 194 can also be configured to rotate aboutpins 202 and 204 (shown in FIGS. 2 and 3), respectively. In certainembodiments, pins 202 and 204 each have a crown to avoid binding. Suchrotation can be effected by a shaft that is coupled to both cams 192 and194, the rotation of which is controlled by the movement of the speedinput. In the exemplary embodiment shown in FIG. 5, the center of arc Ashould be at a “gear neutral” position (i.e., a position where thetransmissions are not transmitting torque to the drive wheels). Whendrive cam 192 and the pin within slot 206 are in position B, the systemis in a neutral or straight ahead position. Position C illustrates thefull forward throttle position for drive cam 192. Position D illustratesa throttle connection point for one embodiment. Position E illustratesthe outside wheel zero position, while position F illustrates the insidewheel zero position. Position H illustrates the point at which drive cam192 rotates. In certain embodiments, drive cam 192 may rotateapproximately 31.5 degrees counter-clockwise for forward movement and14.4 degrees clockwise for reverse.

In exemplary embodiments, distances D1 and D2 should be equivalent toprevent system 100 from providing a change in speed input to thetransmissions when the steering wheel 101 is turned but foot pedal 105has not been depressed. Line I indicates the maximum forward input, lineJ indicates the gear neutral position, Line K indicates the maximumreverse position, and line L indicates the midpoint between maximumforward and maximum reverse positions. In certain embodiments, angle 1(between line L and line J) is 5.07 degrees, angle 2 (between lines Land K) is 12.18 degrees, and angle 3 (between lines L and I) is 12. 18degrees. In exemplary embodiments, the distance between drive cam 192and the gear neutral position should be known and consistent, in so thatlink 182 is in the desired location.

Such a shaft is shown as shaft 199 in FIG. 6; shaft 199 is coupledthrough links to both cams 192 and 194 at coupling points 191 and 193(shown in FIGS. 9A and 10A), and the rotation of shaft 199 is controlledby operation of foot pedal 105. In other embodiments, shaft 199 may becoupled to cams 192 and 194 at other locations (for example, near thetop of cams 192 and 194).

Plate 130 is configured such that the drive wheels of a vehicle can becontrolled independently of each other. As a result, it is possible withthe present systems to rotate one drive wheel (which also may becharacterized as a ground engaging wheel) in one direction and anotherdrive wheel in an opposition direction. In some instances, such adifference in directions makes it possible to achieve a low-radius turn,such as a turn known to those of ordinary skill in the art as azero-radius turn. Further, it is possible with the present systems torotate different drives in the same direction but at different rates.

Referring now to FIG. 7, a top view of plate 130 is shown. A sidesection view of plate 130 taken along line 8-8 in FIG. 7 is shown inFIG. 8. In addition to slots 132 and 134, cam plate 130 includes a hole135 with a spline fit that engages a shaft (not shown) that couplessector gear 120 to cam plate 130. As shown in FIG. 7, slots 132 and 134are not symmetrical about axis X-X (which runs from slot 132, throughthe center of hole 135, and to slot 134). In other words, slot 132 isnot equidistant from the center of hole 135 at all points along slot132. Similarly, slot 134 is not equidistant from the center of hole 135at all points along slot 134. Therefore, as cam plate 130 rotates,followers 142 and 144 (which engage slots 132 and 134, respectively)will not move equal distances. As a result, horizontal bevel gears 155and 165 will move different amounts, causing vertical bevel gears 157and 167 to move different amounts. This will in turn cause shafts 176and 178 to rotate different amounts, leading to different displacementsof steering arms 172 and 174. Consequently, links 182 and 184 will nothave equal movement and the pintle shaft for each drive wheel willprovide a unique drive input to the portion of the transmission systemcontrolling the relevant drive wheel. A difference in rotational speedof the drive wheels of a vehicle can play a role in causing the vehicleto turn. Additional views of alternative embodiment of plate 130 areshown in FIGS. 8B and 8C.

In addition to providing the capability to cause the drive wheels of agiven vehicle to rotate at different speeds and/or in differentdirections, vehicle control system 100 can also be configured to allownon-driving steerable structures (e.g., wheels) to assist in effecting aturn. For example, vehicle control system 100 can include a rack 111(shown in FIGS. 1-4) that engages steering pinion 110. The ends of rack111 may be coupled to an Ackermann steering system 200, such as the oneshown in FIG. 2B. Alternatively, rack 111 may be coupled to anotherother steering system suited for the vehicle's particular application.

The present vehicle control systems, which also may be characterized assteering and speed coordination systems, may include a housing thatprovides a substantially sealed environment (which can be grease-packed)for certain components of the system, such as plate 130, steering pinion110, sector gear 120, first and second followers 142 and 144, first andsecond bevel gear sets 152 and 164, at least a portion of first shaft176, and at least a portion of second shaft 178. A lower portion 112 ofsuch a housing is shown in FIGS. 1-3. A top portion 113 of such ahousing is shown in FIG. 6. The top portion of the housing has beenremoved in FIGS. 1-3 to allow the internal components to be shown.Sealing the various geared components from outside atmosphericconditions may allow for reliable operation and reduce maintenancerequirements of vehicle control system 100.

FIGS. 9A-9D illustrate detailed views of one embodiment of a drive cam192. FIG. 9A illustrates a front view, FIG. 9B illustrates a side view,FIG. 9C illustrates a top view, and FIG. 9D illustrates a section viewtaken along line 9D-9D in FIG. 9C.

FIGS. 10A-10D illustrate detailed views of one embodiment of a drive cam194. FIG. 10A illustrates a front view, FIG. 10B illustrates a sideview, FIG. 10C illustrates a top view, and FIG. 10D illustrates asection view taken along line 10D-10D in FIG. 10C.

FIGS. 11A-11B illustrate detailed views of first steering arm 172. FIG.11A illustrates a front view of steering arm 172, while FIG. 11Billustrates a top view of steering arm 172.

FIGS. 12A-12B illustrate detailed views of first steering arm 174. FIG.12A illustrates a front view of steering arm 174, while FIG. 11Billustrates a top view of steering arm 174.

FIGS. 13A-13B illustrate detailed views of horizontal bevel gear 155.FIG. 13A illustrates a top view of horizontal bevel gear 155, while FIG.13B illustrates a side view horizontal bevel gear 155.

FIGS. 14A-14B illustrate detailed views of horizontal bevel gear 165.FIG. 13A illustrates a top view of horizontal bevel gear 165, while FIG.13B illustrates a side view horizontal bevel gear 165.

FIGS. 15-18 illustrate detailed views of sector gear 120. FIG. 15illustrates a top perspective view, FIGS. 16-17 illustrate side views,and FIG. 18 illustrates a front perspective view.

The table shown in FIG. 15 describes the relationship between variousportions of the system in one embodiment.

FIG. 19 includes data relating to the geometric and physicalrelationship of various components in vehicle control system. The datais measured from a starting neutral point with the steering wheel in aposition to direct the vehicle straight ahead (i.e., the steering wheelis turned zero degrees). The data in the first column represents thelateral movement of the rack for various positions of the steeringwheel, which are shown in the second column. The third column includesdata for the rotation of plate 130, and the fourth column includes datafor the speed ratio of the two drive wheels. The fifth column providesdata for the angle of the front inside wheel (i.e., the front wheel thatis closest to the center of a turn). The sixth and seventh columnsrepresent the vertical position (measured in inches) of links 182 and184 within slots 206 and 208 of drive cams 192 and 194. The data inthese columns is measured from a zero point at which the position oflinks 182 and 184 is not affected by the rotation of drive cams 192 and194 (i.e., the point of rotation for drive cams 192 and 194.) The datain the eighth column represents the amount of rotation (in degrees) ofthe inside steering arm 172 or 174. The ninth column includes data onthe amount of rotation (in degrees) of the inside pin 202 or 204. Thetenth column includes data on the amount of rotation (in degrees) of theoutside steering arm 172 or 174, while the eleventh column includes dataon the amount of rotation (in degrees) of the outside pin 202 or 204.The twelfth and thirteenth columns include data on the lateral speed ofthe inside and outside wheels in miles per hour. The fourteenth andfifteenth columns represent the relationship between the angle of thepintle shaft and wheel speed for a linear system hydrostatictransmission.

It should be understood that the present systems and methods are notintended to be limited to the particular forms disclosed. Rather, theyare to cover all modifications, equivalents, and alternatives fallingwithin the scope of the claims. For example, although the presentsystems have been illustrated and described as having cams defined byslots, the cams could also be implemented as plates with appropriatelycontoured edges along which the relevant followers ride. Thus, those ofordinary skill in the art having the benefit of this disclosure thatslots 132 and 134 in plate 130 could also be implemented as shapedsections of the outer edge of plate 130, and followers 142 and 144 couldbe biased against those shaped edge sections.

The claims are not to be interpreted as including means-plus- orstep-plus-function limitations, unless such a limitation is explicitlyrecited in a given claim using the phrase(s) “means for” or “step for,”respectively.

1.-3. (canceled)
 4. A vehicle control system comprising: a steeringpinion; a sector gear that engages the pinion; a plate that is coupledto the sector gear, the plate having a pair of cams; two followers, oneof which engages one of the cams and the other follower engages theother cam; and a linkage system coupled to the followers, the linkagesystem being coupled a transmission system.
 5. The vehicle controlsystem of claim 4, where the linkage system includes two linkages, thetransmission system includes two transmissions, and one linkage iscoupled to and delivers a drive input to one of the transmissions andthe other linkage is coupled to and delivers a drive input to the othertransmission.
 6. The vehicle control system of claim 5, where each driveinput is based on (i) a speed input or (ii) a speed input and a steeringinput.
 7. The vehicle control system of claim 4, where the plate has acenter of rotation, the cams are slots in the plate, and the slots aresymmetrical about an axis passing through the center of rotation.
 8. Thevehicle control system of claim 4, further comprising a housing in whichat least the steering pinion, the sector gear, the plate, and thefollowers are substantially sealed.
 9. A vehicle control systemcomprising: a steering pinion; a rack that engages the pinion, each endof the rack being coupled to a steerable structure; a sector gear thatengages the pinion; and a linkage system coupled to the sector gear suchthat rotating the steering pinion manipulates the linkage system, thelinkage system being configured to provide at least one drive input to atransmission system.
 10. The vehicle control system of claim 9, wherethe linkage system includes two linkages, the transmission systemincludes two transmissions, and one linkage is coupled to and delivers adrive input to one of the transmissions and the other linkage is coupledto and delivers a drive input to the other transmission.
 11. The vehiclecontrol system of claim 10, where each drive input is based on (i) aspeed input or (ii) a speed input and a steering input. 12.-17.(canceled)
 18. A steering and speed coordination system comprising: asteering pinion; a rack that engages the pinion, each end of the rackbeing coupled to an Ackermann steering assembly; a sector gear thatengages the pinion; a plate coupled to the sector gear, the plate havinga pair of cams; two followers, one of which engages one of the cams andthe other follower engages the other cam; two translating gears, one ofwhich is coupled to one of the followers and the other translating gearis coupled to the other translating gear; two rotating gears, one ofwhich engages one of the translating gears and the other engages theother translating gear; two steering arms, one of which is coupled toone of the rotating gears and the other steering arm is coupled to theother rotating gear, the two steering arms being able to rotateindependently of each other; two drive cam plates, one of which iscoupled to one of the steering arms and the other drive cam plate iscoupled to the other steering arm; a shaft coupled to both drive camplates; and a linkage system that couples the drive cam plates to atransmission system.
 19. The steering and speed coordination system ofclaim 18, where the linkage system includes two linkages, thetransmission system includes two transmissions, and one linkage iscoupled to and delivers a drive input to one of the transmissions andthe other linkage is coupled to and delivers a drive input to the othertransmission, where each drive input is based on either a speed input oron a speed input and a steering input.
 20. The steering and speedcoordination system of claim 18, where each drive cam plate includes aslot in which a drive cam plate follower rides, the position of each ofthe drive cam plate follower being controlled by one of the steeringarms.